Speaking before the House Intelligence Committee, Comey said that he had been authorized by the Department of Justice to confirm the investigation publicly “in an extraordinary step” since the agency does not typically do so with open investigations.

“I have been authorized by the Department of Justice to confirm that the FBI, as part out our counterintelligence mission, is investigating the Russian government’s efforts to interfere in the 2016 presidential election and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government, and whether there was any coordination between the campaign and Russia’s efforts,” he said.

It is the first time the FBI officially confirmed that the scope of the investigation included Trump’s possible ties with Russia, confirming months of sporadic leaks to the press.

Comey added that the investigation “will also include an assessment of whether any crimes were committed” but said he would not be able to speak about any of the specifics of the case because it is an open and ongoing investigation.

“With respect to the President’s tweets about alleged wiretapping directed at him by the prior Administration, I have no information that supports those tweets and we have looked carefully inside the FBI,” Comey said. “The Department of Justice has asked me to share with you that the answer is the same for the Department of Justice and all its components. The Department has no information that supports those tweets.”

Comey reiterated that any wiretapping of a U.S. citizen would require a “rigorous, rigorous process that involves all three branches of government” and has been in place since the 1970s. He said that “no president could” unilaterally order that kind of wiretapping.

There was only one issue on which Comey demurred. Asked about a tweet from Trump which claimed that Obama was “turned down” by the Foreign Intelligence Surveillance Court for a request to do the surveillance, Comey said he could not comment “one way or another” on that subject, but said not to read too much into his non-response.

At the same hearing, National Security Agency Director Mike Rogers also shot down the White House’s repeat of a claim from a conservative pundit that Obama might have asked British intelligence to wiretap Trump.

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“That would be expressly agains the construct of the Five Eyes agreement that’s been in place for decades,” he said.

The British spy service GCHQ had previously rebuffed the claim, calling it “utterly ridiculous.”